Detection of autonomic nervous dysfunction by SL manoeuvre

Abstract

We have evaluated the immediate heart rate response to standing and lying and in 100 Diabetic subjects aged 43 +/- 10 years who underwent five other cardiovascular autonomic tests. Using a specially devised scoring system the patients were divided into three groups: a) 58 subjects without autonomic neuropathy, b) 15 borderliners, c) 27 with autonomic neuropathy. The results were compared with 50, sex and age matched controls. We studied SL1 = ratio between R-R mean before lying and R-R maximum between the 20th to 25th beat and R-R minimum over the first 5 beats after lying. In controls SL1 was 1.35 +/- 0.18 and SL2 was 1.52 +/- 0.23. In diabetic subjects without autonomic neuropathy SL1 was 1.20 +/- 0.86 (p < 0.01), SL2 1.50 +/- 0.02 (p < 0.001). In the group with autonomic neuropathy SL1 was 1.04 +/- 0.02 (p < 0.001) and SL2 was 1.20 +/- 0.09 (p < 0.001). We propose that the lowest normal and highest abnormal limits of SL1 are 1.12 and 1.08 respectively and that normal and highest abnormal limits of SL2 are 1.23 and 1.18 respectively. We suggest the use of SL1 as a pure parasympathetic test and SL2 as a mixed but predominantly sympathetic test in the diagnosis of autonomic neuropathy.